This invention ralates to a novel 4(3H)-quinazolinone compound, and more particularly, a 2-phenylalkyl-3-aminoalkyl-4(3H)-quinazolinone compound having calcium antagonistic, vasodilative, and antihypertensive activities, or a parmaceutically acceptable acid addition salt thereof, to a process for preparing said compound, to a composition having calcium antagonistic activity and comprising said compound as an active ingredient, and to a method of dilating blood vessels or reducing the level of blood pressure based on calcium antagonistic activity.
With respect to a 2-phenylalkyl-3-aminoalkyl-4(3H)-quinazolinone derivative, there has been reported that 2-phenylmethyl-3-(2-diethylaminoethyl)-4(3H)-quinazolinone of the formula: ##STR4## has an antispasmodic activity [Arzneim. Forch. 13, 688 (1963)].
Moreover, although there has been known 2-phenylmethyl-3-(2-aminoethyl)-4(3H)-quinazolinone of the formula: ##STR5## any pharmacological activity thereof has not been reported [J. Indian Chem. Soc., 57, 835 (1980)].
Further, in U.S. Pat. No. 3,558,610, there has been described that a 4(3H)-quinazolinone derivative of the general formula: ##STR6## wherein, R.sup.3 represents a phenyl alkyl group, etc.; R.sup.4 represents a di-lower alkylamino group, etc.; R.sup.5 represents an amino group, an alkanoylamino group, a benzylideneamino group or a nitrofurylideneamino group, is useful as an anti-inflammatory or antimicrobial agent. However, of the compounds described in the Examples of the above Patent, compounds in which R.sup.3 is a phenylalkyl group, or R.sup.4 is a di-lower alkylamino group are only two compounds of the following formulas: ##STR7## and there have been described no compounds in which R.sub.3 is a phenylalkyl group and simultaneously R.sup.4 is a di-lower alkylamino group. The compounds disclosed therein are ones in which R.sup.5 is always an amino group or a substituted amino group and are different from the compounds of the present invention.
Still further, there has been reported that 2-methyl-3-(3-dibutylaminopropyl)-6-chloro-4(3H)-quinazolinone of the following formula: ##STR8## has the inhibitive activity of acetylcolinesterase, although it is not a 2-phenylalkyl-3-aminoalkyl-4(3H)-quinazolinone derivative [Indian J. Pharm., 33, 80 (1971)].